Medicine injection devices and methods

ABSTRACT

A reloadable medicine injector and methods are described in which a barrel with a receiving cavity is adapted to slidably receive a syringe subassembly for axial movement therein. Upon removal of a safety and release of a syringe driver, the syringe driver moves forward and injects the syringe needle. A plurality of penetration controls are shown for controlling injection needle penetration depth. The penetration controls have an abutment and various lengths to provide different needle penetration depth positions. In one form of penetration control a sleeve is used against which the syringe or related parts contact. In another form the front return spring is used as a penetration control. A cushioning ring may be used to reduce syringe breakage. A load distribution and guide ring may be used to distribute loading applied to the syringe and help guide the moving syringe.

TECHNICAL FIELD

This invention relates to injection apparatus and injection ofmedications into body tissues.

BACKGROUND OF THE INVENTION

Self-administering a hypodermic medicine injection is a difficult taskfor many individuals to accomplish. Some individuals experience anaversion to driving a needle into the flesh. The result is that manyindividuals who have health conditions which require periodic injectionsor who face an emergency need for self injection, or a need toadminister an injection on another human or animal will hesitate or insome instances grow faint at the prospect. At least part of therevulsion may stem from watching the needle penetrate the flesh. Anotheraspect comes from the act of forcing the needle into the flesh. To many,the aversion is so substantial that they simply refuse to either selfinject or to administer an injection to another human or animal.

Thus there is a need for a device that will automatically injectmedications without requiring the administering individual to watch theneedle penetrate, and without requiring that the individual actuallysupply the force needed to drive the needle into the flesh and dispensemedicine into the recipient.

Various automatic injection apparatus have been previously developed.Such apparatus may be used to self administer or to administer,injections to others, in such a manner that the apparatus only requirestriggering. Mechanisms provided within the apparatus automatically drivethe needle and dispense the medication. Many prior forms of automaticinjectors are single use, although some allow for reloading ofhypodermic cartridges in which an ampule is provided with a single,fixed needle that openly communicates with the medication in the ampule.

There is also a need for an automatic form of injector that willaccommodate double needle injection cartridges in which two oppositelyfacing needles are slidably mounted by a hub on a medication ampule. Arearward facing one of the needles is situated adjacent a penetrableseal on the ampule so that forced motion of the syringe assembly willresult in the rearward needle piercing the ampule seal and allowing themedication to flow to and out the forward needle. Such action, to bemost beneficial, should be accomplished by the automatic injector.

Another need is for an automatic injector that can be adjusted fordifferent penetration depths, from superficial to subcutaneous tointramuscular and deeper penetration depths. This varies according tothe condition of the patient and/or the medication being administered.This is not just a need related to automatic injectors, but also forindividuals who are unaware of penetration depth requirements.

Need also exists for automatic injectors that can be reloaded withconventional ampules to allow for administration of multiple doses. Suchinjectors allow for removal and replacement of the ampules and re-use ofthe injector mechanism. Another mode of use is as a single ampule forone injection to give a first dose, and then to reset the injector for asecond injection from the same ampule for a second or other multipledoses.

Another pertinent need is the ability to remove the syringe subassemblyfrom the injection device. This may be needed when the injection devicemalfunctions or when immediate administration of a second or subsequentdose is required.

Some or all of the above needs and others are addressed in part or fullymet by various embodiments of the present invention as described below.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a side sectional view of a conventional prior art hypodermicsyringe subassembly of the single needle variety.

FIG. 2 is a side sectional view of a conventional prior art doubleneedle syringe subassembly.

FIG. 3 is a side sectional view of a first embodiment device accordingto the invention in a cocked condition.

FIG. 4 is a side sectional view similar to FIG. 3 showing the needle inan extended condition.

FIG. 5 is a side sectional view similar to FIG. 3 in which a doubleneedle syringe subassembly is in a cocked condition.

FIG. 6 is a side sectional view similar to FIG. 5 showing the doubleneedle syringe assembly in an extended condition.

FIG. 7 is an enlarged sectional detail view of a dosage adjustment andstop arrangement by which multiple dosages may be administered from thesame syringe subassembly.

FIG. 8 is a view similar to the detail view of FIG. 7 showing a stopcollar removed and the remaining components of FIG. 7 in position for asecond dose.

FIG. 9 is an enlarged sectional detail view of a sleeve penetrationcontrol embodiment used in conjunction with a single needle subassembly,with the needle in a retracted position.

FIG. 10 is a view similar to FIG. 9 showing the syringe subassemblyengaging the sleeve penetration control and the needle extended to adesired penetration depth.

FIG. 11 is an enlarged sectional detail view of a compression springpenetration control used in conjunction with a double needlesubassembly, with the needle in a retracted position.

FIG. 12 is a view similar to FIG. 11 only showing the ampule sealpierced, the compression spring penetration control compressed, and theforward needle in an extended position.

FIG. 13 is a sectional view showing an end cap and penetration controlin which any of various length control sleeves can be selected andinstalled for variably controlling needle penetration to variousselected penetration depths.

FIG. 14 is a sectional view showing the end cap and one compressionspring penetration control installed. Various lengths and otherparameters of control springs may be used for controlling needlepenetration to various selected depths.

FIGS. 15A-15F are side views showing different compression springpenetration controls of various lengths and helical advance rates thataffect needle penetration depth.

FIG. 16 is a top view of a preferred stop collar.

FIG. 17 is a side elevational view of the stop collar of FIG. 16.

FIG. 18 is an end view of a preferred sheath remover.

FIG. 19 is a side view of the sheath remover of FIG. 18.

FIG. 20 is a side view of a driver shaft construction having four legs.

FIG. 21 is an end view of the driver shaft of FIG. 20.

FIG. 22 is an end view of a preferred penetration controller sleeve.

FIG. 23 is a side sectional view of the penetration controller sleeve ofFIG. 22 taken along section line 23-23 of FIG. 22.

FIG. 24 is an enlarged partial side sectional view of a muzzle end of apreferred injector construction having a resilient pad and loaddistribution and guide ring positioned between the syringe shoulder. Theinjector is in a cocked condition with the syringe retracted.

FIG. 25 is a view similar to FIG. 24 with the injector shown with thesyringe assembly in an extended position.

FIG. 26 is an enlarged partial side sectional view of another preferredform of the invention in a cocked condition with needle retracted.

FIG. 27 is a partial view similar to FIG. 26 with the injector shownwith the syringe assembly in an extended position.

FIG. 28 is a sectional view showing a preferred auto-injector storagecase according to the inventions.

FIG. 29 is a side view of a bottom part of the case shown in FIG. 28.

FIG. 30 is an enlarged detail sectional view as shown in circle 30 ofFIG. 29.

FIG. 31 is a side view of an upper part of the case shown in FIG. 28.

FIG. 32 is a top end view of the upper case part shown in FIG. 31.

FIG. 33 is a bottom end view of the upper case part shown in FIG. 31.

FIG. 34 is a detail view showing a mounting extension forming part ofthe upper case part of FIG. 31.

FIG. 35 is a side detail view of the mounting extension used to mount aclip to the upper case part of FIG. 31, taken at circle 35 of FIG. 31.

FIG. 36 is an enlarged sectional view taken at circle 36 of FIG. 31.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Introductory Note

The readers of this document should understand that the embodimentsdescribed herein may rely on terminology used in any section of thisdocument and other terms readily apparent from the drawings and languagecommon for such components or operations. This document is premised uponusing one or more terms with one embodiment that will in general applyto other embodiments for similar structures, functions, features andaspects of the invention. Wording used in the claims as filed is alsodescriptive of the invention. Terminology used with one, some or allembodiments may be used for describing and defining the technology andexclusive rights associated herewith.

Syringe Subassemblies

FIGS. 1 and 2 illustrate syringe subassemblies 10 and 11 that arecapable of use with the present invention. The illustrated syringeassemblies or subassemblies 10 and 11 are both of known structure andare commercially available. Exemplary commercial subassemblies aremanufactured, sold, or distributed under the trademark CARPUJECT™ byHospira, Inc. Other subassemblies may also be suitable but may requiresome modification depending on the specifics of construction.

Both subassembly configurations include an ampule 12 that may be a smallglass or plastic vial for containing a measured volume of fluidmedication, medicament or other injectable substance. The quantity ofthe substance may be predetermined, based upon the nature of thesubstance and the anticipated usage. The ampule 12 may be pre-loadedwith the substance and provided by the substance producer ordistributor.

In both versions, the ampule or vial 12 includes a rearward end 13 thatis potentially open to slidably receive a plunger 14. The plunger andplunger piston can be moved axially within the ampule bore 15 byapplication of axial force against the plunger shaft or rod. The plunger14 will thus force the substance out through a hollow needle assembly 16at a forward end of the ampule when the plunger assembly is depressedtoward the forward or needle end.

Subassemblies 10 and 11 differ in the construction of their needleassemblies 16. Subassembly 10 (FIG. 1) is of the fixed needle variety inwhich a fixed hollow needle 17 is mounted by a fixed hub 21 to theassociated ampule 12. The needle 17 openly communicates with thesubstance within the ampule and will eject the substance in response toforced contractionary motion of the plunger 14. A sheath 19 may beincluded to releasably cover the fixed needle 17 for sanitary and safetyreasons, and must be removed or be pierced by the needle beforeadministration of the injection.

Needle assembly 16 for syringe subassembly 11 (FIG. 2) differs from thefixed needle assembly structure described above. Syringe subassembly 11makes use of a double needle assembly 20 in which a double needle hub 90or 21 mounts a seal penetration needle 22 that projects rearwardlytoward a penetrable seal 23 on the associated ampule. Flesh penetrationneedle 24 projects forwardly. In practice, both needles 22 and 24 can bemade integral. In such an integral construction both needles may beformed of the same needle tube, sharpened at both ends and immovablyfixed to needle assembly hub 90.

Hub 90 mounts both needles 22 and 24 and has a cup-shaped receptacle forreceiving the sealed end of the ampule. It also preferably has featuresor provisions to mount the needles in axial sliding relation to a sealretainer 25 of the associated ampule 12. Forced sliding movement of theampule relative to hub 90 will thus cause the seal penetrating needle 22to engage and then pierce the penetrable seal 23. Once seal 23 ispierced, the substance within the ampule may be forced through theneedle or needles 23 and 24 as the injection is administered.

The double needle subassembly 11 may also make use of a protectiveneedle sheath 19. The sheath can vary or be substantially similar, oreven identical to that used for the single needle subassembly 10. Foreither form of subassembly, the sheath may be provided as a rigid cover,or as a flexible member that may be penetrated by the adjacent needleupon application of sufficient axial force. This is disclosed in myearlier issued U.S. Pat. Nos. 5,540,664 and 5,695,472; such disclosuresbeing hereby incorporated by reference into this application. Alsoincorporated by reference are my earlier U.S. Pat. Nos. 5,358,489 and5,665,071.

Injection Device

General Configuration

A reloadable hypodermic injection device according to the invention isshown in the drawings and is identified therein by reference numeral 30.Injection device 30 (FIGS. 3-6) includes a barrel 31 having a muzzle end32, with a needle receiving aperture or passageway 34. A syringesubassembly receiving cavity 35 is situated along and within the barrel31, and is preferably adjacent to and accessible from the muzzle end 32.The cavity 35 is adapted to releasably and slidably receive a syringesubassembly 10 or 11 for movement toward and away from the muzzle end32. The needle assembly 16 is aligned to project through the needlereceiving aperture 34 or through a protective septum (not shown)positioned across and similar to aperture 34.

A syringe driver 36 has an actuator or driver contact 37 that is movabletoward the muzzle end 32 extending into the syringe subassemblyreceiving cavity 35. A penetration controller 38 or other penetrationcontrol is also advantageously provided. The penetration controller mayinclude a penetration control abutment surface 39 which engages theampule assembly, such as at a shoulder or other appropriate featurethereof. The penetration controller has a suitable length andconfiguration from the muzzle end 32 to provide a desired needlepenetration depth or forward needle stop position.

The Barrel

As set forth by example in the drawings, barrel 31 is elongated andtubular, defining the subassembly receiving cavity 35 between a rearwardend 41 and the muzzle end 32. The barrel may be formed of plastic or anyother suitable medically acceptable material of suitable strength.

A driver guide or driver spring guide 33 can be integral with or fittedas a sleeve within the barrel 31 to maintain the driver spring or otherdriver force generator in a desired position, such as coaxiallypositioned therein. As shown, guide 33 functions to guide extension andretraction of the syringe driver spring 36. Guide 33 as shown alsoadvantageously functions as a positioner to accurately locate thesyringe assembly 10, 11 coaxially within the barrel 31.

In the illustrated forms, the rearward barrel end 41 is adapted to mountan annular end piece or firing bushing 43 which is used in conjunctionwith the driver 36, details of which will be described further below. Tofacilitate assembly, the barrel rearward end 41 is preferably moldedabout an inward annular ridge 44. It may alternatively be possible toproduce each part separately and have the annular ridge snap fit withthe firing bushing 43.

The muzzle end 32 in preferred forms mounts a separable nose cap 45 thatdefines the needle aperture 34 or other passageway through which theforward needle extends when fired. The aperture or needle puncturelocation of the nose cap 45 can be releasably attached to the barrel bymeans of interfitting threads 46, rings or other projections. Cap 45 maythus be separated from the barrel to permit access to the barrel cavity35, thereby permitting insertion and removal of the needle subassemblies10 or 11.

Syringe Driver

Driver 36 is used to operate against or be connected through a plungerrod 61 to the plunger or plunger piston 14 of the needle subassembly 10or 11. The plunger rod may be separable or integral with the plungerpiston. The driver is functional to force the subassembly in a forwarddirection to effect needle penetration and to operate against theplunger to inject the ampule contents. Such forces are automaticallyapplied by spring or other suitable driver force initiated through atriggering operation initiated by the user.

Driver 36 as exemplified herein includes the driver bar or shaft 37(FIGS. 3, 4) which is shown within the barrel 31 in a rearwardly cockedposition by a driver release mechanism 53 that may be similar oridentical to that shown in U.S. Pat. Nos. 5,540,664 and 5,358,489 whichare incorporated by reference herein.

Notwithstanding the above incorporated materials, a preferred driver isfurther exemplified herein as including a drive spring 50 that iscompressed when ready or cocked. The drive spring 50 is preferablyguided and contained within the barrel by a spring guide which isadvantageously in the form of a guide sleeve 51. As shown, the guidesleeve is tubular with the guide spring extensible within tubular guidesleeve 51 with portions of the spring slidable therewithin. Otherconfigurations may also be suitable.

The drive spring is selected to provide sufficient stored energy whencompressed to force the needle subassembly forwardly against downstreamresistance and perform needle penetration and injection functions. Itserves to displace the plunger 14 and thus expel the medicamentcontained in the ampule through the injection needle 17.

The drive spring 50 acts against and is restrained by the firing bushing43 at one end. The opposing end bears upon the driver bar 37 whichengages the plunger rod 61. The exemplified driver bar or shaft 37provides a spring engagement shoulder 52 (see FIG. 3) against which theforward end of driver spring 51 engages. As shown, driver release 53includes a barb or barbs 54 that fit through the firing bushing 43central aperture. The barbs are preferably formed on flexible ends ofthe legs of the driver bar or shaft 37.

A safety, advantageously in the form of a safety cap 55, has a forwardlyprojecting pin 56 that is received between the legs of the driver shaftor stem to hold the barbs 54 in engagement with the firing bushing 43and thereby prevent forward movement of the driver bar 37 until thesafety is removed. The safety or safety cap 55 can be pulled rearwardlyto slide the tapered safety pin 56 from between the legs of the driverbar. This frees the barbs to be forced inwardly and radially together.As shown, the barbed legs of driver bar 37 are moved inward by therearward or end of firing sleeve 57 as will be further detailed below.The firing sleeve 57 acts as a trigger.

FIGS. 20 and 21 show the preferred driver shaft or stem has four legs,although other numbers are believed possible. The driver shaft or stemis preferably made using two parts 37 a and 37 b which fit together.These parts can alternatively be made of metal and be molded orotherwise formed as an integral piece.

Radial inward movement of the barbed legs causes the barbs 54 to moveinto a release position as effected by an exterior firing sleeve 57. Inthe design illustrated, the firing sleeve extends over and along theoutside of the barrel. The exposed length of the firing sleeve allowsthe user to grasp the injector by the firing sleeve when the injectionis to be administered.

A forward end of the firing or trigger sleeve can include slots 58 (seeFIGS. 4-6, 9 and 10) that slide along retainers 59 formed on the forwardend of the barrel. The retainers are advantageously in a peninsularconfiguration that provides flexibility to retainers 59 for assembly orpossible disassembly. The interaction between retainers 59 and slots 58prevent the firing sleeve from being unintentionally removed from thebarrel. Such interaction also limits the extent of axial relativemovement while also allowing the parts to be assembled or disassembledby depressing retainers 59.

The firing sleeve 57 includes a trigger head having an opening 60 (FIGS.3-6) which is preferably centrally located. The trigger head of sleeve57 is advantageously beveled along the contact area with barbs 54.Opening 60 receives and inwardly cams the barbs 54 on the legs of thedriver bar 37. This forces the barbed ends together once the safety capis removed and the firing sleeve is moved forwardly with respect to thebarrel. Such action triggers the driver release 53 to free drive spring50. Drive spring 50 thus extends longitudinally, driving the driver bar37 into the plunger shaft and forcing the syringe subassembly forwardlyto administer the injection.

FIGS. 3-6, 7 and 8 show that the driver bar 37 is configured to pushagainst an adjustable plunger rod 61 which is attached to the plunger14. The plunger shaft assembly may be part of the syringe subassembly 10or 11. Alternatively, the plunger shaft or rod 61 may be produced as anintegral part of the driver or as a separate assembly or part. Theplunger shaft may also be made in a non-adjustable configuration, suchas solid or as a non-adjustable assembly.

In the illustrated embodiments, the plunger rod 61 is advantageouslymade up of two axially adjustable components including an actuator ordriver engaging section 62 and a plunger engaging section 63. As shown,sections 62 and 63 are threadably engaged to allow for adjustment of theoverall length of rod 61. This is used to help adjust the dosage orvolume of material dispensed during a single operation of the injectionapparatus.

The illustrated plunger rod 61 is advantageous in that the two axiallyadjustable sections 62, 63 allow for longitudinal rod length adjustment,and for threaded or other connection to the plunger 14. Section 62, asshown, has a head portion and threads which are received into section63. Plunger rod section 63 is coupled, such as by threads, or isotherwise attached to plunger 14. Relative rotation of the two sections62 and 63 can effectively change the plunger rod length, therebyallowing for accurate dosage adjustment, even though the syringes varyin length until adjusted to have the same or other desired length.

It is also possible that a different, conventional form of plunger rods(not shown) might be provided as a part of the syringe subassemblies 10or 11. In such an alternative construction the adjustable rod 61 may notbe needed or used. In such a construction, dosage adjustment may besufficiently accurate by using a properly selected stop collar 64 whichwill be discussed further below. In either construction, plunger rod 61or an alternative integral plunger rod (not shown) can be provided withor as a part of the plunger assembly. With an adjustable plunger rod,such as provided by parts 62 and 63, dosage control is more accuratesince each ampule may vary in length and the adjustment capability canaccommodate for such variations. This may be needed when medicaments areto be dispensed in very accurate dosage amounts. Other medicaments maynot be sufficiently sensitive to dosage amounts and the adjustableplunger costs and adjustment in production may not be needed orjustified.

Dosage Adjustment

The present device is capable of use for single or for multipleinjections. To enable such use, one or more stops in the form of dosestop collars 64 (FIG. 7) can be releasably mounted to the driver 36 or,in the illustrated example, to the plunger rod 61. In the illustratedembodiments, one such collar 64 is shown attached to the rod 61 rearwardof the ampule 12, and forward of the headed section 62 of the plungerrod. The collar 64 and possible multiple such collars are advantageouslypositioned in the forward path of the headed end of the plunger rod 61.Collar or collars 64 stop forward motion of the plunger rod at suchpoint where a selected first dosage has been expelled from the syringesubassembly 10 or 11.

If a second dose remains within the ampule following the firstinjection, the syringe subassembly 10 or 11 can be removed from thebarrel to gain access to collar 64, which then can be removed from theplunger rod 61 to permit further motion of the plunger to deliver theadditional dose.

Following removal of the syringe and collar, the syringe driver 36 canbe recocked, but the process of recocking requires holding the barrel 31in reaction to the force needed to recompress the drive spring 50. Thismay be difficult in the constructions shown and described herein due tothe firing sleeve or trigger handle 57 extending over the majority ofthe length of the barrel 31. In other embodiments or with care thesyringe can be recocked by holding the barrel and inserting a screwdriver or similar tool and depressing the driver bar 37 and associateddriver spring 50. If recocked, the syringe subassembly can bere-inserted into the barrel for automatic injection of a second oranother dose which becomes available as the plunger is permitted furtherforward travel in response to subsequent triggering.

The length dimension of the collar 64 or multiple collars can beselected according to the desired dosages to be administered. Althoughnot illustrated, multiple collars may be stacked along the plunger rod,with each collar representing a dose of medicament or other substancefrom the ampule. Separate injections may be performed following removalof successive stop collars. Alternatively, in instances where singledosages are desired, a single or even no stop collar may be selectedaccording to the desired single dosage.

Stop collar 64 may be made having different sizes of arcs. In some casesthe collars extend fully about the plunger shaft. A currently preferredstop collar has an arcuate size of about 180-200 arcual degrees. FIGS.16 and 17 show a currently preferred design having an open side and anarcuate size 110 of about 185-190 arcual degrees. The relatively openside 111 is advantageously provided with end faces 112 which are beveledto converge inwardly. These features provide easier installation of thestop during production and easier removal by a user after the first orother prior dose has been administered.

Another feature shown in FIGS. 16 and 17 that facilitates removal ofstop collar 64 is the provision of ribs, flutes, striations or otherfriction features 120. These friction features improve manual graspingof the collar to remove it from the outside of plunger shaft 61. Thisconstruction allows a user to remove the collar using the thumb andforefinger from a single hand. It improves the removal such that twohands are not necessary as was the case in earlier designs. Thisimprovement greatly reduces the chance that the action of removing thestop collar does not lead to accidental depression or upward movement ofthe plunger which may compromise the accuracy of the second dose amount.

The outside of the stop collar 64 may also advantageously be providedwith circumferential segments 121 between the friction features 120 anda flat segment 122. Flat segment 122 facilitates installation of thestop collar upon the plunger rod 61.

The inside surface 124 is preferably semi-cylindrical and sized to fitthe plunger rod 61. The particular size may vary depending on the sizeof ampule and size and type of plunger rod used.

Nose Cap or Muzzle End Piece

FIG. 6 shows that nose cap 45 is advantageously removable from thebarrel to allow insertion and removal of a syringe subassembly. Cap 45may be generally in a cup shaped form to be received upon the forwardend of barrel 31. In the illustrated embodiments, the nose cap fits overthe outward surface of the barrel. The nose cap is secured thereon usingthreads or other suitable connection joint. Depending on the specificconstruction used, the nose cap may alternatively fit within the barrel.

It is preferred for accuracy in needle penetration depth control thatthe nose cap 45 be secured axially against a positive stop such as ashoulder 47 formed along the barrel 31. Shoulder 47 can be providedalong the barrel to accurately locate an installed nose cap 45 in arepeatable manner. This is preferred to provide axial accuracy to therelative location of the nose cap 45 upon the barrel. This is desirablesince the nose cap may be removed and re-mounted repeatedly to enableremoval and replacement of ampule and needle subassemblies.

It is advantageous for accurate positioning of the nose cap 45 to usethe threads 46. Threads 46 are provided along the nose cap 45 and barrel31 to facilitate secure engagement between the abutment shoulder 47 andnose cap 45. However, fastening arrangements between the nose cap 45 andbarrel 31 may be used other than the illustrated threads 46. Forexample, a bayonet, barb, snap fit or other releasable connectionarrangement could also be used to releasably interlock the nose cap withthe adjacent forward part of barrel 31 to provide repeated accuratepositioning.

The forward end of nose cap 45 defines the illustrated needle apertureor passageway 34. Aperture or passageway 34 is advantageously sized toreceive needle sheath 19 therein. As illustrated in FIGS. 9 and 10, theneedle safety sheath can project through the aperture 34. Sheath 19 maybe provided with a blunt forward end which may extend forward of themuzzle end 34. The projection of the sheath facilitates removal of thesheath immediately prior to use.

The outside of nose cap 45 may advantageously be provided with ribs,flutes, striations or other friction surface to facilitate installationand removal of the nose cap from the barrel. The construction shown usesa threaded connection between the nose cap and barrel. Thus an exteriorfriction surface allowing torque to be applied is preferred in suchconstructions. A preferred friction surface has minute linearlongitudinal striations (not shown).

Sheath Remover

Removal of the sheath 19 from the syringe sub-assembly 10 or 11 can beaccomplished or facilitated by provision of a sheath remover 80 that isreleasably mounted at the muzzle end 32. FIG. 18 shows an exemplarysheath remover 80 from the forward end. FIG. 19 shows a side view of thesheath remover. The construction illustrated includes a sheath gripper81. The gripper has a central aperture 85 that is disposed insubstantial coaxial relation to the needle receiving aperture 34 of thenose cap. The central aperture 85 receives the sheath 19 therethrough.

Gripper 81 also preferably includes radially inward projecting fingers82 that flexibly grip the sheath 19 behind a lip 89 (see FIG. 3) nearthe tip of the sheath remover. The inwardly projecting fingers 82provide sufficient flexibility to allow the sheath remover to be pushedonto and installed over the enlarged end of the sheath near lip 89.

A collar portion 84 extends rearwardly of the end surface 87 and isreceived over the nose cap 45. The collar portion 84 may be providedwith circumferential ribs 83 to improve manual grasping of the sheathremover so as to facilitate pulling the sheath and sheath remover fromthe injector.

Fingers 82 will flex rearwardly during removal of the sheath and catchon lip 89 and securely grip the sheath 19 when the remover is pulledforwardly. In doing so, the fingers will catch behind the lip andfurther bind and pull the sheath 19 from the needle assembly hub 90(FIG. 3) to expose the outwardly directed needle 17. The sheath andsheath remover can later be re-installed, in an instance where itbecomes desirable to re-cover the needle for safety purposes.

Penetration Control

Syringe driver 36, when triggered, forces the syringe subassembly 10 or11 forwardly within barrel cavity 35. This drives the needle 17forwardly through the aperture 34 to penetrate the flesh of the patient.Depth of penetration according to the present invention isadvantageously determined using a penetration controller 38 (FIGS. 9-15)and other alternative forms described herein. The penetration control orcontroller stops penetration at a desired repeatable penetration depthof needle 17. This is different than dose control, since the penetrationdepth is gauged from the nose cap which actually contacts the fleshduring automatic injection.

Penetration controller 38 in preferred forms is located along the barrel31, with an abutment surface 39 spaced from the muzzle end 32 at aselected and desired needle penetration depth stop position. Thepenetration control is engaged by the syringe assembly to stop forwardmotion of the flesh penetration needle 17 at the selected penetrationdepth. This is done to remove the necessity for the user to determinepenetration depth. By providing a penetration control, the device can beselected or adjusted so the needle will penetrate only to a desireddepth as an automatic function of the device. Adjustment is preferablyprovided using a penetration sleeve, spring or other penetration controlelement.

First Exemplary Penetration Controller

In one preferred form, the penetration control is provided bypenetration controller 38. Penetration controller 38 may be constructedmore specifically in the form having a tubular sleeve 70 portion heldwithin the nose cap 45. FIGS. 22 and 23 show penetration controller 38in detail. The penetration controller includes a control sleeve 70 whichhas a flange 170 attached thereto. It is advantageous that the sleeve 70and flange 170 be shaped for frictional engagement within the nose cap45. This is desirable so that removal of the nose cap will also resultin removal of the penetration control 38. This is facilitated by flangelobes 170 a which tend to cant within the nose cap cavity (FIG. 22).This mounting arrangement also helps to provide repeatable and accurateaxial positioning of the abutment surface 39 within the barrel 31 andrelative to the outer front face of the nose cap or other fleshcontacting face of the injector. The flange sleeve 70 and thickness offlange 170 define the length of the controller. The end of the sleeveopposite the flange provides a syringe abutment surface 39 at a selecteddistance from the muzzle end. In this example, the surface 39 is at therearward end of the sleeve and faces the needle subassembly within thecavity 35.

The overall length of controller 38 is typically defined by the lengthof sleeve 70. The length may be selected from a group having varyingaxial dimensions to effect different needle penetration depths. Thus onesleeve may be useful for subcutaneous injections, while another may beselected when deeper intramuscular penetration is required. A selectionof sleeves of differing axial lengths may be used dependent upon themedicine being provided in the injector or for specific depths ofdesired needle penetration.

The sleeve 70 is also useful to receive a forward or return spring 71,preferably of the coiled compression variety, which can be disposedwithin the barrel, between the nose cap 45 and needle hub. The front orreturn spring 71 is provided to yieldably resist forward motion of theneedle subassembly to hold the subassembly in the retracted positionuntil the syringe driver 36 is triggered. Spring 71 also helps to reducethe impact of the syringe assembly with the penetration control, thusreducing or eliminating breakage of the hub or penetration controller.

The penetration control unit 38 can be used to secure the return spring71 in position within the barrel, using flange 170. This also helpsretain the spring for removal along with the nose cap 45 (FIG. 13). Tothis end, the spring diameter may be enlarged at its forward end 72 inorder to provide a friction fit between the spring 71, sleeve 70 and thenose cap 45, while allowing the remainder of the spring free movementwithin the confines of the sleeve portion 70.

One of the important functions of the return springs is to keep theneedle in a hidden, retracted position after the sheath is pulled off.This prevents the user from seeing the needle and prevents the user frombeing scared due to needle fright. The return spring acts quickly onremoval of the sheath to return the syringe up inside the barrel suchthat the user has no visual reminder that there is a needle positionedin a hidden position therein.

By providing the return spring 71 and sleeve 70 arrangement describedabove, the fully compressed axial spring length will be less than thesleeve length. Thus the penetration depth is determined by the selectedlength of sleeve 70 and flange 170. With proper design, the yieldableresistance offered by spring 70 will remain within suitable limitsregardless of the sleeve length selected to adjust penetration depth.

The above arrangement (in which the return spring 71, selected sleeve 70and flange 170, and nose cap 45 are interconnected) is advantageous tosimplify attachment to and removal from the barrel 31. A user wishing togain access to the needle sub-assembly for replacement or for secondinjection purposes, need only unthread the nose cap 45 from the barrelend. The return spring 71 and sleeve 70 will move along with the nosecap to permit free access to the cavity 35. The lobes 170 a also mayinteract with the internal threads of the nose cap to help prevent thenose cap, sleeve and front spring from flying freely when disconnectedfrom the barrel.

Second Exemplary Penetration Controller

Another form of the penetration control may be provided in a form andconstruction which uses a selected spring of a particular fullycompressed length dimension. FIGS. 15A-15C illustrate by way of exampleseveral springs 75, 76, 77 that will have different fully compressedlengths but similar lengths when installed in device 30. In each one ofthe springs, one of the spring ends will function as the abutmentagainst which the needle hub engages or other parts engage as explainedfurther below. The needle hub will stop when the spring is fullycompressed and the desired penetration depth is attained.

By using a spring 75 that is selected for a desired compressed length,the spring itself becomes the penetration controller when fullycompressed between the needle hub and the nose cap 45. Thus the springcan have dual functions: offering yieldable resistance to slow forwardmotion of the adjacent needle subassembly; and stopping such forwardmotion once the needle reaches the selected penetration depth and thespring becomes fully compressed.

The selected springs 75-77 can be made to fit frictionally within thenose cap 45 in order to keep the spring and nose cap together. Thissimplifies access to the cavity 35 and a needle assembly therein. Italso mitigates flying discharge of the nose cap and spring whendisconnected. Thus, the cap 45 and spring can be assembled so both canbe simultaneously removed from the barrel as a unit. Changing from onespring to another to accommodate different penetration depths is asimple matter of removing the nose cap from the barrel and changing thespring. Alternatively, an assembly including a nose cap and differentspring can be used to change penetration depth.

FIGS. 15D, 15E and 15F show additional novel concepts in using theforward spring for penetration control and absorption of energy from themoving drive and syringe assembly. FIG. 15D shows spring 78 in a freeand uncompressed condition. Spring 78 has three sections, 78 a, 78 b and78 c. Section 78 a has spaced helical or spiral windings which may becollapsed due to force applied by the driver through the syringeassembly. Section 78 b includes one or more dead windings which areclose or tight and are normally not compressible due to application ofaxial compressive force to spring 78. Section 78 c is enlarged end coilsor windings that are radially contracted when installed in the nose capreceptacle and serve to tie the spring and nose cap together.

By adjusting the relative proportion of sections 78 a, 78 b and 78 c,the compression and energy absorption properties of the forward springcan be adjusted to provide different penetration control and differentdeceleration characteristics. More dead coils reduce energy absorptionas the forward spring is compressed because there are fewer active coilsto absorb energy. Thus the increase in dead coils can be used tomaintain adequate syringe power for injection and dispensing of themedication.

FIG. 15E shows spring 78 in a fully compressed but axially aligned andstacked condition. This occurs when the spring has stronger and/or largespring wire. The spring made with stronger wire will thus reach a fullycompressed state and then relatively abruptly stop at the demonstratedpenetration depth for that design of spring.

FIG. 15F shows a spring 79 similar to spring 78 with similar sections.Spring 79 does, however, demonstrate a different type of behavior uponfull compression. The spring wire is made finer and less strong. Thiscauses the spring to compress and then distort into a distortedcollapsed condition. This condition provides a two-stage compressionaction. In the first stage or phase, the spring compresses in a typicalor nearly typical stack arrangement. In the second stage or phase, thespring distorts with various windings being forced to radially change,thus distorting and collapsing with some winding either moving inside ofother windings or overriding other windings. This constructioneffectively provides shock absorption and energy absorption capabilitiesthat reduce shock after the spring has been fully compressed and allowenergy absorption after full compression into a stacked array and helpsor eliminates breakage of the syringe hub and other parts of theinjector. It also provides cushioning as the syringe and driverdecelerate to a stopped condition.

As examples, syringes made of wound or coiled music wire having wirediameter size of about 0.015 inch tend to collapse and distort asindicated in FIG. 15F. In comparison, springs wound from music wirehaving a diametrical size of 0.018 inch tend to remain in a stacked coilarray as indicated in FIG. 15E.

These are current preferred wire sizes for injection devices using onlya spring as the penetration control. Although such constructions are notas precise in demonstrating consistent penetration depth, they aresufficiently consistent for the administration of many medicines. Theyalso are more economical to produce and eliminate the penetrationcontrol 38 having tubular sleeve 70 and flange 170 or other similarrelatively inelastic penetration control elements. They are also lessexpensive to produce and assemble.

Use of finer spring wire has another beneficial effect. The springs tendto distort more easily and further reduce the risk that a nose cap andspring assembly fly away upon removal, such as when preparing foradministration of a second or subsequent dose.

Syringe Assembly Front Spring Load Distribution, Guidance & Cushioning

FIGS. 24 and 25 show front portions of an injection device having manyof the same features as described elsewhere herein. Description of thecommon features are made using the same reference numbers and thedescription which is common will not be repeated.

The embodiment of FIGS. 24 and 25 differ in that a load distributionring 171 is provided to act in several capacities. The first capacity isto distribute the forces developed between the front spring 75 and thesyringe, particularly at the syringe assembly hub 21. The secondcapacity is to act as a guide piece to help maintain the coaxialposition of the syringe assembly hub within the barrel cavity. The thirdcapacity is to also distribute and equalize force about the annularabutment 170 so that the forces developed against the syringe are notconcentrated.

The ring 171 is preferably made about the same size as the barrel cavityportions within which the guide ring moves during operation of theinjector. This is advantageously done by making the ring within a rangeof about −0.001 inch to about −0.004 inch compared to the adjacentbarrel cavity interior diameter. Other size relationships are alsobelieved operable.

Ring 171 is preferably made from a stainless steel or other suitablematerial which is strong and sufficiently stiff to help distribute theload evenly which is applied across the ring.

FIGS. 24 and 25 further show a resilient cushion in the form of acushion or pad ring 172 which surrounds the syringe hub 90. The cushionis preferably made from an elastomer material such as natural rubber orSantoprene 8281-45-med having a durometer value of about 45. In theuncompressed state the cushioning pad ring 172 is about 0.030 inchsmaller in diameter than the load distribution and guide piece 171. Thisallows the pad ring to expand outwardly in a radial direction when loadis applied thereto as the syringe is driven against the front spring andresistance is developed in association with dispensing the fluidmedication from the front needle. An outer diameter which is larger andcloser to the adjacent barrel internal diameter may lead to lateralstrain that causes the pad ring 172 to develop frictional drag againstthe barrel bore. This in turn requires more driver force to be providedin order to overcome the friction and creates added stress and strain onthe syringe and other parts of the injector.

FIGS. 26 and 27 show another embodiment similar to that shown in FIGS.24 and 25. The embodiment of FIGS. 26 and 27 is not provided with a loaddistributor and guide ring like ring 171 of FIGS. 24 and 25. Instead,the cushion pad 172 directly bears on the syringe hub and the frontspring. Although this construction is not as preferred as that shown inFIGS. 24 and 25, it is believed operable. Due to the less uniform loadapplication a harder and more durable elastomer material may be neededto allow repeated use of an injector so constructed.

In either of the constructions shown in FIGS. 24-27, the cushion pad 172has been found to be superior at moderating forces experienced by thesyringe hub 90 and thus reduces the risks of failure or breakage of thehub or other portions of the syringe assembly.

Summary of Front Return Spring Functions

The front or return spring thus performs a number of importantfunctions. It maintains the syringe assembly in a retracted positionprior to use, such as during handling, shipping, carrying by the userand other situations. Any one of these may by routine or accident causeforce to be developed on the syringe and return spring. The returnspring thus maintains or helps to maintain the syringe in a retractedposition prior to firing but does so in a manner that absorbs shock andminimizes the risk of syringe ampule breakage.

The return springs also serves to help keep the injection needle upinside the nose cap or barrel to keep it in a hidden position to preventuser alarm at sight of the needle.

Another function of the return spring is to counteract against the drivespring upon triggering of the injection. The drive spring acceleratesthe syringe down the barrel and the kinetic and well as stored springenergy is preferably dissipated to prevent or reduce the risk of syringeampule breakage or breakage of other components of the forward end ofthe injector which in one way or another must take the force anddissipate the energy. Dissipation of energy is particularly enhancedwhen the spring deforms as illustrated in FIG. 15F.

Another important aspect of the forward or return spring is in someembodiments to provide for proper insertion of the seal insertion needle22 into and through the ampule seal 23. This is accomplished byselecting a return spring which develops the return force needed tocause seating of the ampule and insertion of needle 22 at or slightlybefore final penetration depth is achieved. Thus, the spring may providefor delayed administration of the medicine until the needle penetrationdepth is proper.

In some forms of the inventions the front or return spring may by itselfserve as the penetration control. This simplifies the construction ofthe injector and saves costs where the required consistency ofpenetration control for the medicine being used is within thedemonstrated consistency of the penetration controller spring being usedis satisfactory. Where these parameters are met the more complexpenetration control sleeve can be eliminated.

A still further advantageous function of the front return spring is tohold or help hold the spring with the nose cap. This is accomplished inthe illustrated embodiments by using a spring which has enlarged coilstoward the forward end. These larger coils serve to maintain the springwith the nose cap when the nose cap is removed. This may prevent orminimize any risk of the nose cap and spring flying off. This propertyof retaining the spring and nose cap also simplifies handling the nosecap by keeping the nose cap, spring and any tubular penetration controltogether as a cap and penetration control assembly.

Thus it can be seen that the front return spring performs a surprisingnumber of different functions and advantages or combination of differentfunctions and combinations of advantages.

Considerations for Double Needle Syringe Subassembly

Description to this point has been generic with respect to the differentneedle subassemblies 10, 11 because both needle forms can be utilizedwith the structure described. With respect to the double needlesubassemblies, however, the penetration depth controller 38 and thesyringe driver 36 are configured to perform an additional function ofpenetrating the seal 23 using penetrating needle 22.

The seal penetrating task is accomplished as the triggered syringedriver 36 forces the needle subassembly forwardly. As the subassembly 11moves forwardly, the hub 21 slides into abutment with the syringeabutment surface 39 of the penetration controller. Continued appliedforce will cause the associated ampule 12 to slide on forwardly althoughthe hub 21 and needles 22 will remain axially stationary in relation tothe abutment 39. The forward moving ampule will thus be penetrated bythe rearwardly projecting needle 22.

It should be appreciated that tissue penetration depth is notderogatorily affected by the ampule piercing operation. The forwardneedle 24 will move toward the selected penetration depth as the hub 21moves to engage the abutment surface 39. Continued forward force againstthe syringe subassembly by the driver 36 will cause the injection needle24 to continue being extended as the rearward needle 22 penetrates seal23. Hub 21 is thus seated as full penetration of the forward needle 24occurs. Further movement of the driver causes the ampule medication tobe dispensed and injected.

The double needle subassembly 11 may in some cases be preferable to theopen communication single needle subassembly 10. This can be visualizedin that the injection needle will be fully or almost fully penetratedinto the flesh before the injected medicine is dispensed into the flesh.With the single needle syringe there is a potential effect of puttingmedication above the final needle injection depth. So in actualoperation the double ended needle may provide more controlled and/orreproducible dispensing of the medicine at the final needle depth. Thisis what is done in the hospital setting with a manual injection in thatthe doctor or nurse first places the needle to the desired depth andthen presses the plunger. It also prevents loss of medicine as theinjection needle passes through intermediate tissue.

The wire diameters for some return springs are suitable for achievingthe seating and desired insertion of the ampule by needle 22 at the sametime the injection needles reach their desired final penetration depth.This is caused by the springs either being weak enough (lower springrate) so that the penetration control sleeve 38 performs the finalseating and insertion of needle 22 through seal 23. In otherembodiments, such as when the penetration control is solely by thespring, the spring rate of the return spring is selected to similarlyprovide for seating and insertion of needle 22 through seal 23 also ator near the desired final penetration depth. In either case, thisprovides proper administration into the tissues which are the intendedtissue for the desired final penetration depth.

The injector also performs another important novel function when usedwith double needle syringe assemblies, such as 11. Such assembliesrequire the needle assembly to be seated manually or with a deviceholder before performing manual injections. The action of firing theinjector carrying a double needle syringe causes the needle assembly toseat or mate with the sealed ampule. Thus a manually useful syringe isautomatically formed. This indicates the multiple functions provided byinjectors described herein. One function is to automatically administerthe first dose. Another function is to seat the double needle syringeassembly with the sealed ampule to form a manually administrable syringefrom a dual needle syringe and sealed ampule. A further function is toprovide a reliable backup syringe for situations where the syringe maybe misused and the second dose is the only dose and can be administeredmanually for ultimate reliability as may be dictated by difficultsituations on the battle field or in other situations.

Storage and Carrying Case

FIGS. 28-36 show a preferred outer or carrying case in which theinjectors described herein may be carried in a protected manner. FIG. 28shows that the preferred carrying case 200 has a lower or bottom part201 and an upper or top part 202. The upper and lower parts are joinedby a detachable joint used to keep the parts together until such time asan injector, such as injector 30, is needed and can be removed from thecarrying case. Before explaining the operation of the carrying case, adetailed explanation of the features thereof will now be given.

Carrying case 200 is designed to carry an injector with the driver andtrigger end of the injector inserted into the upper case part 202. Themuzzle and needle end of the injector is inserted into the lower casepart 201.

In the preferred construction shown, a bottom end receptacle 205receives the muzzle end of the injector. This is preferably done so thatthe sheath remover front wall 82 bears upon a support ledge 206. Ledge206 is preferably padded with an annular pad 209. This constructionprevents loading of the exposed needle sheath to forces that developduring movement, handling and mishandling (such as dropping) of thecarrying case with injector supported therein.

The length between ledge 206 and the upper end of the case top piece 202is nearly equal but shorter than to the length of the injector betweenthe safety cap or other top end piece and the face surface 82 of thesheath remover. This construction advantageously provides a small amountof clearance so that the injector is not loaded in an axial manner whenstored in the carrying case.

FIG. 28 shows that the upper part 202 of the carrying case isadvantageously provided with a clip mount 206 which can be welded to theupper part 202 or integrally formed therewith during molding of theupper part. The clip mount is used to mount a clip 207 which is similarto a clip on a pen. The clip is preferably made of metal having springproperties that hold the clip end 208 against the upper case piece 202.The clip may be used to help hold the carrying case in a user's pocketor in luggage, brief cases, cosmetic bags or in or on other parts of auser's garments or accouterments.

FIGS. 34 and 35 show the clip mount 206 in greater detail. Otherconfigurations are also possible. In any design the mount is preferablydurable and prevents the clip 207 or mount 206 from being broken fromthe carrying case upper part 202.

FIG. 28 shows that the upper and lower case parts are preferablyconstructed so as to form a detachable joint 210. Although a threadedjoint is acceptable, it has been found more preferable to have a jointwhich can be easily and quickly disconnected so that in an emergency theinjector can be accessed quickly to administer a medicine without delay.In the construction shown, the bottom part 201 includes an insertionpart 220 (FIG. 29) which is sized and shaped to fit within an insertionreceptacle 230 (FIG. 36) formed on the open complementary end of theupper case part 202. Insertion section 220 is advantageously providedwith a retainer projection or projections 221 which are received withinan annular recess 231 (FIG. 36) to provide a catch or mating engagementwhich retains the two case parts together until needed by a user.

The connection joint 210 is also advantageously provided with quickrelease which can be provided in the form of two projections 241 whichare received in complementary receptacles formed on the mating part 201.The projections are preferably semicircular to mate into semicircularreceptacles 242 adjacent to the insertion part 220. This configurationallows the case to be easily opened by twisting the two case parts 201and 202 relative to each other only a relatively small angulardisplacement. The semicircular projections and receptacles thus interactto cam the two case parts away from one another and dislodge theretainer projections 221 from the annular recess 231. Thus, by merelytwisting the two case parts less than about 1/10th of a rotation, thecarrying case is opened and the injector contained therein may be easilyremoved.

FIG. 36 also shows a shoulder 232 which is recessed an amount so thatthe insertion section 220 extends into the joint receptacle bringing theend surface of the insertion part into engagement with the shoulder 232.This also facilitates proper extension of the insertion part into thereceptacle so that the projections 221 properly fit into the annulargroove 231.

Sharps Disposal

The novel constructions shown herein are also advantageous in that theyare adapted to provide a sharps container or containers for holding thesyringe assembly after the medicine has been injected. In one form thesyringe assembly is removed or withdrawn from the injector through themuzzle end without a needle sheath thereon. The return spring andrelated parts forward of the syringe assembly are also removed. With theneedle end of the syringe first, the syringe is then inserted into thebarrel cavity in reverse orientation. The nose cap 45 without returnspring and any penetration control sleeve is then connected or attachedto the barrel to secure the syringe therein for safe handling and properdisposal.

In another form the syringe assembly is inserted into the carrying caseand the two parts of the carrying case are rejoined. The carrying caseacts as a portable sharps container. Thus the invention may also providea safe means for carrying the syringe and associated needle or needlesto a larger sharps disposal container for shipping and disposal. It mayalso be placed in the carrying case to provide a combination which isextremely resistant to breakage and needle exposure.

Added Methods and Operation

In addition to the various descriptions given elsewhere hereinconcerning methods and operation of the inventive components, thefollowing added explanation is provided to supplement the description.

A method aspect according to the present invention is provided fordriving a syringe needle 24 or 17 to a selected penetration depth.Aspects of the method will be discussed along with a description ofoperation and use of the invention.

The process initially includes placing the injector in a cockedposition. This is preferably done during manufacture. The injector iscocked with the safety cap 55 removed and pressing the driver bar 37rearwardly. The barbs 54 on the driver shaft are moving and thenextending into hole 60 at the trigger end of firing sleeve 57. Thisperforms a compressing of the drive spring 50 and catching of the barbs54 upon annular piece 43. Once the device is cocked, the safety cap 55can be installed to prevent accidental firing of the driver. This actionplaces the pin 56 between the barbed legs of the driver bar 37. Pin 56prevents the barbed ends from moving toward one another and releasingthe driver bar or shaft. This readies the apparatus for reception of theselected syringe assembly.

Then the process involves selecting a suitable syringe subassembly. Theselecting involves syringes having the desired fluid volume, injectionneedle length and durability for the intended purposes. In preparationfor installation of the syringe subassembly, the plunger rod 62 may beattached to the syringe plunger 14, which allows for performance of astep in which at least one stop collar 64 may be attached to the plungerrod 61 for dosage control if the syringe is provided with a multipledose charge. If the plunger rod 61 can be adjusted for axial length,then adjusting the plunger rod occurs at this time to provide a desiredor consistent discharge volume or dose. Thus a step of determining adosage to be dispensed from the apparatus is accomplished. Onceadjusting and/or determining step has been completed, the dose settingstep is complete.

Further preferred methods include inserting a selected syringesubassembly through the open forward end of barrel 31. The methodsfurther include locating and installing the syringe subassembly to adesired position within the interior of barrel 31. This is accomplishedwith the nose cap 45 removed and by sliding the selected syringesubassembly with the open end 13 first, into the barrel cavity.

The above steps and procedures according to the inventions may ingeneral be accomplished with either the fixed needle or double needlesyringe subassemblies 10 or 11.

Further processes according to the invention may also include adjustingpenetration depth. Adjusting penetration may be accomplished byselecting a desired penetration controller 38, spring penetrationcontrol or other penetration control, having a length which positionsthe abutment surface 39 at a desired location. This may include aselectable number of penetration stop positions. This can beaccomplished while the nose cap 45 is separated from the barrel 31either by placing a selected length of penetration control sleeve 38into the nose cap, or by placing a selected penetration control spring75-79 into the nose cap. A combination of control spring and fixedcontrol element may also be possible.

In the example illustrated in FIGS. 3-6, the sleeve type penetrationcontroller 38 is used, and is frictionally positioned within the cap toabut the nose cap interior front wall adjacent the needle aperture 34.Return spring 71 is also placed within sleeve 70, prior to installingthe controller and spring subassembly into the nose cap interior cavity.This is preferably done with the enlarged end of the spring engaging thefront, flanged end 170 of sleeve 38.

The spring, penetration controller and nose cap assembly can then beinstalled to the barrel. This is advantageously done in the illustratedembodiments by threading the nose cap onto the barrel until the stopshoulder 47 is engaged by the rearward end of the nose cap, to assureproper axial spacing between the syringe abutment surface 39 and thesyringe hub. The return spring may be made to abut a ring-shapedstainless steel guide and load distributor 171 (FIGS. 24 and 25) to helpassure accurate firing and less decelerated stopping of the syringesubassembly.

Alternatively, a spring of selected compression length (for example, oneof the springs 75-79), can be used to determine penetration depth. Inthis aspect, a spring is selected that has a compressed axial lengthrelated to a desired needle penetration depth. The selected spring isthen mounted to the nose cap 45, such as by frictionally sliding thespring into place within the cap and/or along with the guide 171. Nowthe end of the spring facing the syringe hub becomes the syringeabutment surface and the penetration depth will be gauged by the fullycompressed length of the spring. The spring may have various number ofactive coils and in some designs dead coils to help provide desiredpenetration with sufficient energy for penetration. Once the selectedspring is mounted within the nose cap, the assembly can be threaded ontothe barrel to a point where the stop shoulder 47 is engaged.

The sheath remover 80, if not already in position on the nose cap 45,can be slid into position on the nose cap 45, to position the sheathengaging fingers 82 over the sheath. The fingers will perform byflexing, thereby allowing the sheath remover to act by sliding over theextent of the needle sheath 19 that is exposed forwardly of the nose cap45.

Once the nose cap 45 and sheath remover 80 are in place and the safety55 is attached, the device is loaded, cocked and in a safe conditionnearly ready for use. The device can be safely carried or stored in thiscondition until such time that an injection is to be administered.

The following discussion will describe a single dose use, and a doubledose use of the illustrated and other auto-injectors according to theinvention. The described uses are both possible using the same orsimilar procedures with both a single fixed needle syringe subassembly10, or the double needle subassembly 11.

Prior to injection, the user can remove the protective sheath 19 fromthe needle subassembly by moving, such as by sliding, the sheath remover80 forwardly. This performs a disengaging step, freeing the sheathremover from the nose cap 45. The sheath remover fingers 82 perform byengaging and catching or binding against the sheath lip 89. Furtherremoval of the sheath remover applies axial forces upon the sheath thatact by pulling the sheath outwardly through the needle aperture 34 inthe nose cap 45. The sheath remover thus performs an action of removingthe sheath from the syringe assembly and other parts of the autoinjector.

The user may perform a removing step to remove the safety 55 from theopposite end of the barrel. This is advantageously done by pulling thesafety and attached safety pin 56 from between the barbed legs of thedriver bar 37 or other driver shaft assembly. This arming step involvesremoving or disabling the safety, thus readying the injection device fordose administration.

To perform injecting, the user presses the nose cap against the tissuearea to be injected. The pressing action causes movement of the firingsleeve 57 forwardly relative to the barrel. The barbs on the driver baror shaft assembly will move toward one another collapsing inwardly byengaging the barbs against the walls of opening 60. This action releasesthe driver bar, which is now allowed to move forwardly, such as bysliding, in response to force applied by the driver. This forcing of thedriver shaft serves to free the driver release into a driving actionwherein the driver bar moves forward and acts by engaging the plungerrod. The driving action also forces the needle subassembly forward. Thisacts by penetrating the adjacent tissue of the user with the needle andalso serves by penetrating any second needle through the seal of theampule.

As the needle subassembly moves forwardly, the return spring 71 orselected penetration control springs 75-79 are acted upon to perform acompressing of the forward spring. The spring, nose cap and anypenetration control acts by restraining and stopping the forwardlymoving needle hub. In arrangements in which the engaged end of thereturn spring also constitutes the syringe abutment surface, theselected spring will fully compress at a preselected axial location,stopping needle penetration at the desired penetration depth. The samepenetration depth can be effected in arrangements in which the returnspring 71 compresses to a point where the needle hub engages the fixedabutment surface 39 on the selected sleeve type penetration controller70. Penetration depth is determined by the selected axial position ofthe abutment surface, whether it be on a penetration control sleeve orby fully collapsing a spring having a desired fully compressed length.

Once the abutment surface or full spring compression point is reached,the drive spring 50 will continue pushing the plunger rod forwardly,dispensing medicine. In instances where a single needle syringesubassembly 10 is used, continued forward motion of the plunger willresult in injection of the medication. Medication is also injected whena double needle assembly 11 is provided within the barrel 31, but afterthe ampule is driven forward onto the seal penetrating needle 22.

Medication will be injected as the spring 36 performs by forcing theplunger forwardly. Such forcing continues until such time that theplunger shaft engagement head engages any desired stop collar 64 orstack of stop collars. This marks the end of the injection, and theprescribed dosage amount will have been injected at the selectedinjection penetration depth. The device is now ready for eitherrecocking and reloading with another syringe subassembly, or forpreparation to inject a second dose or subsequent doses of medicationwhich are still within the ampule due to stopping action performed byone or more stop collars 64.

The penetration depth and the dosage amount are controllable asdiscussed above. This is advantageously done by provision of theremovable or adjustable stop arrangements within the barrel 31. Thedosage can be selectively controlled by the stop collar 64 and theadjustable length plunger rod 61. Penetration depth can be controlled byselecting the axial position at which the needle hub is stopped withinthe barrel 31 as a function of the selected or adjusted penetrationcontrol, such as by penetration controller 38 or the collapsed conditionof a penetration control spring.

The novel methods may also include administering a second injection.According to some forms of the invention, this can be done with the samesyringe assembly. Alternatively it may be done using a second orsubsequent syringe assembly. When using a single syringe, the userperforms by removing the nose cap 45 and sliding or extracting thesyringe assembly from the barrel cavity. Any stop collar 64, collars orportions thereof can then be removed, such as by laterally removing thecollar, collars or portions thereof from the plunger rod, therebyallowing the plunger to be pushed further forward within the ampule toinject another dose. This is preferably used to administer a second dosein a manual mode of operation.

If the injector is to be used for administering the second dose, thenthe injector is recocked by removing the syringe assembly and thenholding the barrel and depressing the driver using a screw driver orother tool which is extended into contact with the driver bar or shaft37.

The safety, such as safety cap 55, can now be placed back over therearward end of the device. This safety placing action causes insertingof safety pin 56 wherein the driver bar legs form a safety openingreceiving the safety pin 56. The installed safety pin performs byholding them apart and rendering the device into a safe condition,thereby avoiding unintentional firing.

When the syringe subassembly 10 or 11 is received back in the barrel(such as with stop collar 64 removed), the ampule will slide backfurther into the barrel until it abuts with the spring guide sleeve 33(FIG. 8). The subassembly will be held in this position by the spring 71(or by the selected other springs 75-79) as the nose cap 45 is replaced.Replacement of the nose cap completes the needed steps for a second orsubsequent use of the device to deliver a second auto-injected dose. Ifthe injection is to be given immediately, there is no need to replacethe sheath and sheath remover. However if the second injection is to bedelayed for a time, it is possible for the sheath 19 and sheath remover80 to be re-installed even though the needle is now carried safelywithin the nose cap. Alternatively, the sheath and sheath remover arenot reinstalled to reduce risks of injury or contamination.

Administration of the second dose may be accomplished automatically inthe same manner as described above. In such operation the driver willfunction to depress the plunger through the axial distance previouslyoccupied by the stop collar 64.

The injection apparatuses according to this invention may also allow theadministering of a second or subsequent dose in a manual manner. In suchalternative mode of operation the syringe assembly is removed from thebarrel in a manner the same as or similar to that described above. Ifthe initial dose does not work with sufficient effectiveness, then theuser may manually insert the forward needle into the flesh of thepatient and depress the plunger rod with the thumb. This procedure maybe used when recocking the driver is difficult or impossible, or tospeed administration of the second or subsequent doses.

More than one stop collar can be provided, and more than two injectionsfrom the same syringe may be administered. It is also noted that theinjection device may be provided without a stop collar, so the syringewould be used only for one auto-injection. Excess medicine can beprovided in the syringe for manual administration. Dosage amounts can bemore accurately determined by axially adjusting the headed part 62 ofthe plunger rod 61. In either case, the device can be re-used. In afirst mode of operation, the device can be reset by recocking andinstalling the same syringe previously used. In a second mode ofoperation, the device can be reset in the manner described above and asecond syringe subassembly can be installed and used and operated asdone with the first syringe.

Manner of Making

Many of the components of the auto-injector are preferably made bymolding, such as injection molding, a suitable medical grade transparentplastic into the configurations shown and described herein. Metal piecesare turned or fabricated according to various well-known metal workingtechniques. Preferred components for the injector are detailed below orstated above.

The plunger shaft 63 is preferably made from a metal material, such as2024 grade aluminum which is anodized with a clear material per militaryspecification MIL A 8625 C clear.

The tubular penetration control sleeve is preferably made from asuitable plastic material which is molded into the desired shape andsize. A preferred material is sold under the name Celcon TX90 Plus.Others are possible such as Nylon 6 (Capron 8253), or M270 Celcon.

The springs are preferably made from steel music wire having highstrength for the small size and excellent spring retention capabilities.The return spring may vary, but in some forms 0.015 inch diameter hasbeen preferred, type A228; however, heavier wire may be preferred invarious constructions. The drive spring is preferably ASTM-A313 type17-7 PH stainless steel wire, 0.033 inch diameter.

The driver release annular piece 43 is preferably made from a suitablesteel, such as 12L14 Grade A steel, which is preferably zinc plated perASTM B633-85 Type III SEI.

The nose cap, safety cap piece and sheath remover are preferably madefrom a molded plastic such as Amoco #4039 polypropylene or Polymerland#1120.

The needle sheath is preferably made from high density polyethyleneSpec. #MS-4079.

The carrying case is preferably made from a non-transparent or opaquecolored plastic material, such as polypropylene, for example, Rexene#17C9A polypropylene.

The spring clip on the carrying case is preferably made from a suitablesteel, such as a chrome or other plated steel which does not easilyrust, or from a suitable stainless steel, such as 0.010 inch 301stainless steel half hardness with #2 finish.

The sheath remover and safety cap are preferably made from DuPont Zytel101L.

The firing sleeve and plunger adjustment screw are preferably made ofBayer Markrolon #2607-1112 polycarbonate.

The drive spring bushing is preferably made from Amoco #4039polypropylene.

The barrel is preferably made from Plexiglass DR 101 Acrylic. The springguide for the drive spring is preferably made from Dow 478-27-W highimpact polystyrene.

The stop collar and bushing edge against which it bears are preferablymade from Amoco #4039 polypropylene or Polymerland #1120.

The spring release is preferably made from 8 NOS high density 70/30brass CL C2600 per ASTM B36-91A.

Further Aspects and Features

The above description has set out various features and aspects of theinventions and the preferred embodiments thereof. Such aspects andfeatures may further be defined according to the following claims whichmay individually or in various combinations of the recited features helpto define the inventions in accordance herewith.

Interpretation Note

The invention has been described in language directed to the currentembodiments shown and described with regard to various structural andmethodological features. The scope of protection as defined by theclaims is not intended to be necessarily limited to the specificfeatures shown and described. Other forms and equivalents forimplementing the inventions can be made without departing from the scopeof concepts properly protected hereby.

1. An apparatus forming a medicine injection device adapted for use byan individual in emergency or field conditions for injection of medicinethrough skin of a user in either an automatic mode of operation or asecondary manual mode of operation, comprising: a tubular barrel ofsuitable strength to maintain an elongated substantially rigid tubularconfiguration during use having a muzzle end with a needle receivingaperture; a syringe subassembly receiving cavity situated along thebarrel adjacent the muzzle end, adapted to releasably and slidablyreceive a syringe subassembly for movement toward and away from themuzzle end with a needle of the syringe subassembly being capable ofprojection through the needle receiving aperture; a syringe subassemblyheld within the syringe subassembly receiving cavity and movabletherein; a syringe driver connected to the barrel, and having a driverbar movable toward the muzzle end against the syringe subassembly andinto the syringe subassembly receiving cavity to move the syringesubassembly for administration of medicine therefrom; a penetrationcontroller mounted at the muzzle end of the barrel and having a syringesubassembly abutment spaced from the muzzle end to achieve a desiredneedle penetration depth position; said penetration controller includinga front spring that maintains the syringe subassembly in a retractedposition within the tubular barrel such that the needle of the syringesubassembly is within the barrel unless the syringe driver is activatedto extend the needle of the syringe subassembly projecting it throughthe needle receiving aperture; a detachable nose cap at the muzzle endof the barrel which allows a user to gain access to the syringesubassembly for the administration of a second or subsequent dose ifneeded by a user, wherein said detachable nose cap and penetrationcontroller with front spring are connected to form a cap and penetrationcontrol assembly which can be removed by release of the detachable nosecap; wherein the penetration controller includes at least onepenetration control sleeve which is connected to the nose cap with atleast portions of the front spring therebetween.
 2. An apparatus forminga medicine injection device adapted for use by an individual inemergency or field conditions for injection of medicine through skin ofa user in either an automatic mode of operation or a secondary manualmode of operation, comprising: a tubular barrel of suitable strength tomaintain an elongated substantially rigid tubular configuration duringuse having a muzzle end with a needle receiving aperture; a syringesubassembly receiving cavity situated along the barrel adjacent themuzzle end, adapted to releasably and slidably receive a syringesubassembly for movement toward and away from the muzzle end with aneedle of the syringe subassembly being capable of projection throughthe needle receiving aperture; a syringe subassembly held within thesyringe subassembly receiving cavity and movable therein; a syringedriver connected to the barrel, and having a driver bar movable towardthe muzzle end against the syringe subassembly and into the syringesubassembly receiving cavity to move the syringe subassembly foradministration of medicine therefrom; a penetration controller mountedat the muzzle end of the barrel and having a syringe subassemblyabutment spaced from the muzzle end to achieve a desired needlepenetration depth position; said penetration controller including afront spring that maintains the syringe subassembly in a retractedposition within the tubular barrel such that the needle of the syringesubassembly is within the barrel unless the syringe driver is activatedto extend the needle of the syringe subassembly projecting it throughthe needle receiving aperture; a detachable nose cap at the muzzle endof the barrel which allows a user to gain access to the syringesubassembly for the administration of a second or subsequent dose ifneeded by a user, wherein said detachable nose cap and penetrationcontroller with front spring are connected to form a cap and penetrationcontrol assembly which can be removed by release of the detachable nosecap; wherein the penetration controller includes a penetration controlsleeve with at least one flange having at least one lobe which engageswith features of the nose cap to help maintain connection of said capand penetration control assembly.
 3. An apparatus forming a medicineinjection device adapted for use by an individual in emergency or fieldconditions for injection of medicine through skin of a user in either anautomatic mode of operation or a secondary manual mode of operation,comprising: a tubular barrel of suitable strength to maintain anelongated substantially rigid tubular configuration during use having amuzzle end with a needle receiving aperture; a syringe subassemblyreceiving cavity situated along the barrel adjacent the muzzle end,adapted to releasably and slidably receive a syringe subassembly formovement toward and away from the muzzle end with a needle of thesyringe subassembly being capable of projection through the needlereceiving aperture; a syringe subassembly held within the syringesubassembly receiving cavity and movable therein; a syringe driverconnected to the barrel, and having a driver bar movable toward themuzzle end against the syringe subassembly and into the syringesubassembly receiving cavity to move the syringe subassembly foradministration of medicine therefrom; a penetration controller mountedat the muzzle end of the barrel and having a syringe subassemblyabutment spaced from the muzzle end to achieve a desired needlepenetration depth position; said penetration controller including afront spring that maintains the syringe subassembly in a retractedposition within the tubular barrel such that the needle of the syringesubassembly is within the barrel unless the syringe driver is activatedto extend the needle of the syringe subassembly projecting it throughthe needle receiving aperture; a detachable nose cap at the muzzle endof the barrel which allows a user to gain access to the syringesubassembly for the administration of a second or subsequent dose ifneeded by a user, wherein said detachable nose cap and penetrationcontroller with front spring are connected to form a can and penetrationcontrol assembly which can be removed by release of the detachable nosecap; wherein the penetration controller includes a penetration controlsleeve with a flange having lobes which engage with features of the nosecap to help maintain connection of said cap and penetration controlassembly.
 4. An apparatus forming a medicine injection device adaptedfor use by an individual in emergency or field conditions for injectionof medicine through skin of a user in either an automatic mode ofoperation or a secondary manual mode of operation, comprising: a tubularbarrel of suitable strength to maintain an elongated substantially rigidtubular configuration during use having a muzzle end with a needlereceiving aperture; a syringe subassembly receiving cavity situatedalong the barrel adjacent the muzzle end, adapted to releasably andslidably receive a syringe subassembly for movement toward and away fromthe muzzle end with a needle of the syringe subassembly being capable ofprojection through the needle receiving aperture; a syringe subassemblyheld within the syringe subassembly receiving cavity and movabletherein; a syringe driver connected to the barrel, and having a driverbar movable toward the muzzle end against the syringe subassembly andinto the syringe subassembly receiving cavity to move the syringesubassembly for administration of medicine therefrom; a penetrationcontroller mounted at the muzzle end of the barrel and having a syringesubassembly abutment spaced from the muzzle end to achieve a desiredneedle penetration depth position; said penetration controller includinga front spring that maintains the syringe subassembly in a retractedposition within the tubular barrel such that the needle of the syringesubassembly is within the barrel unless the syringe driver is activatedto extend the needle of the syringe subassembly projecting it throughthe needle receiving aperture; a detachable nose cap at the muzzle endof the barrel which allows a user to gain access to the syringesubassembly for the administration of a second or subsequent dose ifneeded by a user, wherein said detachable nose cap and penetrationcontroller with front spring are connected to form a can and penetrationcontrol assembly which can be removed by release of the detachable nosecap; wherein the penetration controller includes a penetration controlsleeve with a flange having lobes which engage with thread features ofthe nose cap to help maintain connection of said cap and penetrationcontrol assembly.
 5. An apparatus forming a medicine injection deviceadapted for use by an individual in emergency or field conditions forinjection of medicine through skin of a user in either an automatic modeof operation or a secondary manual mode of operation, comprising: atubular barrel of suitable strength to maintain an elongatedsubstantially rigid tubular configuration during use having a muzzle endwith a needle receiving aperture; a syringe subassembly receiving cavitysituated along the barrel adjacent the muzzle end, adapted to releasablyand slidably receive a syringe subassembly for movement toward and awayfrom the muzzle end with a needle of the syringe subassembly beingcapable of projection through the needle receiving aperture; a syringesubassembly held within the syringe subassembly receiving cavity andmovable therein; a syringe driver connected to the barrel, and having adriver bar movable toward the muzzle end against the syringe subassemblyand into the syringe subassembly receiving cavity to move the syringesubassembly for administration of medicine therefrom; a penetrationcontroller mounted at the muzzle end of the barrel and having a syringesubassembly abutment spaced from the muzzle end to achieve a desiredneedle penetration depth position; said penetration controller includinga front spring that maintains the syringe subassembly in a retractedposition within the tubular barrel such that the needle of the syringesubassembly is within the barrel unless the syringe driver is activatedto extend the needle of the syringe subassembly projecting it throughthe needle receiving aperture; a detachable nose cap at the muzzle endof the barrel which allows a user to gain access to the syringesubassembly for the administration of a second or subsequent dose ifneeded by a user, wherein said detachable nose cap and penetrationcontroller with front spring are connected to form a cap and penetrationcontrol assembly which can be removed by release of the detachable nosecap; wherein the penetration controller includes a penetration controlsleeve with at least one lobe that engages in the detachable nose cap.6. An apparatus forming a medicine injection device adapted for use byan individual in emergency or field conditions for injection of medicinethrough skin of a user in either an automatic mode of operation or asecondary manual mode of operation, comprising: a tubular barrel ofsuitable strength to maintain an elongated substantially rigid tubularconfiguration during use having a muzzle end with a needle receivingaperture; a syringe subassembly receiving cavity situated along thebarrel adjacent the muzzle end, adapted to releasably and slidablyreceive a syringe subassembly for movement toward and away from themuzzle end with a needle of the syringe subassembly being capable ofprojection through the needle receiving aperture; a syringe subassemblyheld within the syringe subassembly receiving cavity and movabletherein; a syringe driver connected to the barrel, and having a driverbar movable toward the muzzle end against the syringe subassembly andinto the syringe subassembly receiving cavity to move the syringesubassembly for administration of medicine therefrom; a penetrationcontroller mounted at the muzzle end of the barrel and having a syringesubassembly abutment spaced from the muzzle end to achieve a desiredneedle penetration depth position; said penetration controller includinga front spring that maintains the syringe subassembly in a retractedposition within the tubular barrel such that the needle of the syringesubassembly is within the barrel unless the syringe driver is activatedto extend the needle of the syringe subassembly projecting it throughthe needle receiving aperture; a detachable nose cap at the muzzle endof the barrel which allows a user to gain access to the syringesubassembly for the administration of a second or subsequent dose ifneeded by a user, wherein said detachable nose cap and penetrationcontroller with front spring are connected to form a cap and penetrationcontrol assembly which can be removed by release of the detachable nosecap; wherein the penetration controller includes a penetration controlsleeve with a flange and a spring that having at least one enlarged endwinding that is positioned between the flange and the detachable nosecap.